In offshore drilling operations, the operator will perform drilling operations through a drilling riser. The drilling riser extends between the subsea wellhead assembly at the seafloor and the drilling vessel. The drilling riser is made up of a number of individual joints or sections. These sections are secured to each other and run from a riser deploying floor of the drilling vessel. The drilling riser also normally has a number of auxiliary conduits that extend around the main central pipe. Some of the auxiliary conduits supply hydraulic fluid pressure to a subsea blowout preventer (BOP) installed on the subsea wellhead to control the well.
A BOP assembly may be part of a stack assembly which may be located at the lower end of the riser extending downward from the drilling vessel. The BOP stack assembly will normally contain shear rams, pipe rams, variable bore rams, annular closure member, and a quick disconnect mechanism for disconnecting from the riser in the event of an emergency. When actuated, shear rams will close the through bore and also shear pipe in the well, such as drill pipe, tubing, or casing. A shear blade may be attached to a ram block via a plurality of bolts that pass through a front face of the shear blade and threadingly engage the ram block. Further, the bolts aid in resisting forces during shearing and also from the wellbore pressure. However, a counterbore for each of the bolts on the front face of the shear blade reduces the area of the blade, thereby reducing the strength of the blade. An improved technique for attaching the shear blade to the ram block is therefore needed.